1. Field of the Invention
The present invention relates to the repair of building foundations by underpinning. Additionally, the present invention relates to underpinning pile assemblies having both concrete piles and steel pipes.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
There is a type of precast concrete pile used in the underpinning of building foundations comprised of vertically stacked, unconnected, precast concrete segments. These segments are pressed or driven vertically into the soil one at a time until adequate load capacity is obtained. This type of pile is distinctive in that it can be installed with almost no clearance, usually beneath an existing structure.
Although serviceable, this pile has several significant disadvantages: (a) the pile segments are not aligned, other than being stacked on each other, and detrimental misalignments can occur, (b) independent inspection of the installed pile depth is only possible by providing full-time inspection personnel during installation to monitor the quantity of pile segments used at each pile location, and (c) the complete pile is an unreinforced stack of precast concrete segments.
Misalignment of the segments as they are installed can produce several conditions detrimental to the future pile stability. Lack of proper independent inspection of pile depth can lead to inadequate pile penetration, which in highly expansive soils produces an unstable installation subject to continued movements caused by seasonal change in soil moisture content. An unreinforced or non-continuously reinforced pile is subject to permanent separation at segment joints or breakage at segment midpoints when installed in clay soils having high shrink-swell potentials.
In the past, various patents have issued relating to the devices for installing underpinning piles retroactively for the support of a structure. For example, U.S. Pat. No. 5,288,175, issued on Feb. 22, 1994 to D. W. Knight, describes a continuously reinforced segmental precast concrete underpinning pile. A method of installing the underpinning pile is used where a high-strength strand aligns the precast segments during installation. The strand provides a means for measurement of the pile penetration depth. The strand continuously reinforces the pile when bonded or anchored upon completion. This patent describes a further process whereby a strand is affixed to a first pile segment prior to being driven into the earth. The first pile segment, along with the attached strand, is driven a desired distance into the earth from the supporting structure. The strand will extend upwardly and outwardly from an end of the first pile segment. The second pile segment then slides along the strand until the second pile segment contacts an end of the first pile segment. The second pile segment is then driven into the earth for a desired distance. Ultimately, after each of the pile segments is driven a desired distance into the earth, a cap member is affixed to the top of the array of pile segments so as to be placed under the foundation of the structure. In “chicken pot pie” type soil conditions, where a softer layer of earth is located between a stiff crust and a denser, lower layer, the method of this patent fails to utilize existing pile structures. As such, there is a considerable cost associated with the driving of multiple pile segments through the softer layer of the earth. With such soil structures, it would be desirable to use the existing pile structures if possible.
U.S. Pat. No. 5,399,055, issued on Mar. 25, 1995 to E. T. Dutton, Jr., teaches a device and method to level and repair a failed concrete foundation. A series of cylindrical pile segments are jacked into the soil to a pre-determined depth so as to attain sufficient skin friction. Water jetting is utilized during the jacking process to loosen and remove soil. Reinforcing steel is inserted into the stacked column of cylindrical pile segments and grout is further pumped into the cylindrical pile segments to suitably fix the reinforcing steel to the inside of the cylindrical piles. This forms a single shaft pile so as to eliminate or reduce pile deflection and shear. Once again, the patent fails to make use of existing timber piles.
U.S. Pat. No. 5,713,701, issued on Feb. 3, 1998 to F. S. Marshall, describes a foundation piling which has a metallic piling sleeve member filled with solidified or cured cementitious material and a hollow, cylindrical outer sleeve member having a diameter larger than that of the metallic sleeve member. The outer sleeve member is placed generally concentrically around the piling sleeve member. The piling and the outer sleeve member are vertically driven into the soil. Further metallic piling sleeves and outer sleeve members are successively vertically driven into the soil until the piling is complete and the metallic piling sleeve and outer sleeve members abut one another in vertical relation.
U.S. Pat. No. 6,179,526, issued on Jan. 30, 2001 to Knight et al., shows a method of forming a pile isolation void. This method includes the steps of forming a foundation pile having an enlarged cross-section within a specific localized section, and driving the foundation pile a desired distance into the earth so as to form a pile isolation void directly above the enlarged cross-section. The enlarged cross-section can be located at the bottom of the foundation pile or along the length of the foundation pile. The pile isolation void is an annular void extending around the foundation pile above the enlarged cross-section. This pile isolation void can be filled with a material, such as liquid, gel, or a solid material different than the material of the pile or of the earth.
U.S. Pat. No. 6,200,070, issued on Mar. 13, 2001 to D. W. Knight, shows process of installing piles for supporting a structure upon the earth. This process includes the steps of forming a receptacle in a first pile segment, affixing an end of a strand into the receptacle such that the strand extends outwardly from the first pile segment, sliding a second pile segment onto the strand until the second pile segment contacts a surface of the first pile segment, and driving the second pile segment a desired distance into the earth. The receptacle is formed in the first pile segment while the first pile segment is in the earth.
U.S. Pat. No. 6,543,967, issued on Apr. 8, 2003 to F. S. Marshall, shows a staggered rebar design for concrete pilings. A first pile segment is driven into the earth. Two support rods of varying length are positioned and grouted into a passage running through the segment. The first support rod is one-half of the height of the pile segment, while the second is one and one-half times the height of the pile segment. An additional pile segment is driven on top of the first segment. Support rods which are twice the height of a single segment are positioned and grouted into the passage.
U.S. Pat. No. 6,634,830, issued on Oct. 21, 2003 to F. S. Marshall, describes a method and apparatus for post-tensioning segmented concrete pilings. A cable anchor serves as a base segment for multiple concrete piling segments. After installing all the concrete segments on top of the base segment, a cable is inserted into passages in the segments. The cable is threaded through the completely installed piling segments and into the cable anchor. After the cable bottoms out in the cable anchor, upward tension is applied to the cable. As the cable is pulled, cable lock members in the cable anchor increase gripping pressure as the cable tension increases so as to solidly anchor the end of the cable in the cable anchor.
U.S. Pat. No. 6,718,648, issued on Apr. 13, 2004 to T. S. Knight, shows a method of measuring a length of a pile which supports a structure upon the earth. This method includes the steps of affixing a flexible strand to a first pile segment, driving the first pile segment a desired distance into the earth such that the flexible strand extends along the length of the first pile segment along an exterior surface thereof, and driving a plurality of additional pile segments into the earth such that the pile segments reside upon an end of the first pile segment. The flexible strand extends along a length of the plurality of additional pile segments on the exterior surface thereof.
U.S. Pat. No. 6,722,820, issued on Apr. 20, 2004 to F. S. Marshall, provides a method of installing grout within a piling. Pile segments are driven into the ground on top of each other so as to form a piling. A single piling passageway is formed when the pile segments are in alignment. An alignment securing assembly is placed in the passageway. Vibrations are sent through the piling so that grout will not gather in the upper portions of the passageway before the lower portions of the passageway are filled with grout. The alignment securing assembly uses an anchoring device that is lowered and set in the passageway so that tension can be applied by a cable.
U.S. Pat. No. 6,763,636, issued on Jul. 20, 2004 to M. Dimitrijevic, provides a method and apparatus for lifting and leveling an existing building. At least a first non-cylindrical support section and a second support section are coupled together by a fastening device. A jack is used to raise the foundation of the existing building to a desired height. The apparatus is attached to the foundation of the building from underneath the building or from a location adjacent a side of the building.
U.S. Pat. No. 6,799,924, issued on Oct. 5, 2004 to Kight et al., describes a segmented concrete piling assembly with steel connecting rods. A first starter pile segment is driven into the soil adjacent the structure. A connecting rod is inserted into the upper end of the starter pile segment. A second or follower pile segment is placed on the upper end of the starter pile segment, over the connecting rod, and driven into the soil. This further drives the starter pile segment into the soil.
U.S. Pat. No. 6,881,012, issued on Apr. 19, 2005 to G. R. Covington, teaches a foundation repair system and method of installation. This system has continuously interlocked segmental precast concrete underpinning piles. A cooperating extension on one segment engages a cooperating depression on an adjacent segment. This aligns the precast segments during installation so as to provide a laterally stable pile.
U.S. Pat. No. 6,951,437, issued on Oct. 4, 2005 to D. B. Hall, provides a building foundation support and repair system. The system has a column of generally cylindrical pile sections driven into the earth below the edge of the foundation, and has an earth-penetrating bit attached to the lowermost pile section. The earth-penetrating bit includes a center post member extending within a bore in the lowermost pile section and/or a sidewall journaling the lower end of the lowermost pile section. The bit is connected to an elongated rod extending through the series of connected pile segments and is used to drive the bit rotatably during installation of the pile sections. This minimizes lateral excursion of the support system during and after installation of the column of pile sections.
U.S. Pat. No. 7,108,458, issued on Sep. 19, 2006 to Davie, Jr. et al., discloses a method and apparatus for repairing building foundations by segmented underpinning In particular, there are a plurality of pile segments that are reinforced in a longitudinal direction. A precast starter segment has a coil embedded in one end of the segment and a coil rod protruding from the other end. The starter segment is driven into the earth with its protruding rod end facing downwardly. A second segment is interlocked with the first by threading the second segment's rod and into the coil of the starter segment. The second segment is screwed into the first segment until the two segments lock together.
U.S. Pat. No. 7,195,426, issued on Mar. 27, 2007 to D. May, provides a structural pier and method for installing the pier. The pier includes a pier shaft, a bracket mounted to a top end of the pier shaft that supports the weight of the foundation, and a pair of braces that extend laterally from the pier shaft and mount to the foundation.
U.S. Pat. No. 7,429,149, issued on Sep. 30, 2008 to Price et al., provides a sleeved, segmented support product for supporting a foundation. This product comprises support segments that can be assembled together into a variable-length pile. The segments assemble together telescopically so that adjacent segments are held in coaxial relation and resist radial misalignment that can reduce the load-bearing capacity of the support product.
U.S. Patent Publication No. 2008/0317556, published on Dec. 25, 2008 to M. Price, describes a pier system for supporting a building. The pier system includes a plurality of swaged pier segments in which each swaged pier segment is operable to be connected to another of the swaged pier segment. A hinged lifting platform is secured to an uppermost one of the swaged pier segments. At least one intermediate swaged pier segment is connected to the uppermost swaged pier segment. An encasement is provided for partial receipt of the intermediate swaged pier segment.
One of the problems associated with these prior art underpinning pile assemblies is the use of concrete pile segments. In certain earth formations, it becomes very difficult to drive these pile segments the proper and desired distance into the earth. In particular, when the earth is particularly hard or dense, great forces would be required so as to cause the pile segments to reach their intended depth. As such, it would be desirable to provide an underpinning pile assembly which allows the underpinning piles to reach the proper and desired depth in a simple, convenient and efficient manner.
In those prior art patents that utilize steel sleeves or other steel systems, the steel members are generally positioned adjacent to the building foundation. As such, the steel members are driven into the earth in an area that is exposed to oxygen and moisture. Over time, these steel members can become corroded and deteriorate to the point that they are no longer effective and no longer adequately supporting the steel structure. As such, a need has developed so as to provide an underpinning pile assembly in which any steel components are effectively positioned so as to minimize exposure to moisture and oxygen.
Steel underpinning pile systems are often affixed to the foundation and driven at an angle into to the earth in a location below the foundation. This can create a great deal of torque onto the beam of the foundation and onto the steel pier. As such, a need has developed so as to provide an underpinning pile assembly which avoids the affects of the torquing of the beam and the steel pier.
It is an object of the present invention to provide an underpinning pile assembly which facilitates the ability to install the underpinning pile assembly to greater depths.
It is a further object of the present invention to provide an underpinning pile assembly which allows the assembly to be introduced into dense, hard, or compacted soils in a convenient and efficient manner.
It is a further object of the present invention to provide an underpinning pile assembly which effectively reduces the effective moisture and oxygen upon the steel member employed in the underpinning pile assembly.
It is a further object of the present invention to provide an underpinning pile assembly which eliminates the torquing of the beam of the foundation or the torquing of the steel members used in the underpinning pile system.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.